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Air Pollution

Air Pollution. Chapter 10. Major Air Pollutants. Sulfur Dioxide Nitrogen Oxides Carbon Oxides Particulate Matter Photochemical Oxidants Lead and Other Metals Volatile Organic Compounds. Sulfur Dioxide. Description: Corrosive gas Source: Combustion of coal and oil,

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Air Pollution

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  1. Air Pollution Chapter 10

  2. Major Air Pollutants • Sulfur Dioxide • Nitrogen Oxides • Carbon Oxides • Particulate Matter • Photochemical Oxidants • Lead and Other Metals • Volatile Organic Compounds

  3. Sulfur Dioxide • Description: Corrosive gas • Source: Combustion of coal and oil, volcanic eruptions, forest fires, combustion of fossil fuels (derived from plant and animal remains that contain sulfur) • Effects: Respiratory Irritant, harmful to plant tissue

  4. Nitrogen Oxides • Description: • NO is a colorless, odorless gas • NO2 is a pungent, reddish brown gas • Sources: • Naturally: forest fires, lightning, microbial action in soils • Anthropogenic sources: motor vehicles, stationary fossil fuel combustion • Nitrogen gas, N2, makes up 78% of the atmosphere. • All combustion in the atmosphere leads to the formation of some nitrogen oxides. • Nitrogen oxides play a role in forming tropospheric ozone and other components of photochemical smog.

  5. The figure below shows the process of acid rain formation from nitrogen dioxide and sulfur dioxide. Acid Rain • This picture shows a forest devastated by acid rain in the Jizera mountains of the CzeckRepulic. 

  6. Carbon Oxides • Carbon Monoxide is a colorless, odorless gas • Formed during incomplete combustion of most matter • A common emission in most vehicle exhaust • Significant air pollution in urban areas, and indoor (exhaust systems on natural gas heaters malfunction) • Carbon dioxide is a colorless, odorless gas • Formed during complete combustion of most matter • Absorbed by plants during photosynthesis • Released during respiration • More favorable than incomplete combustion which forms carbon monoxide • However burning fossil fuels is responsible for excess CO2 in the atmosphere, therefore it has become a major pollutant

  7. Particulate Matter • Solid or liquid particles suspended in air • Sources: • combustion of wood, animal manure and other biofuels, coal, oil, and gasoline • Can come from road dust, rock-crushing operations • Diesel- powered vehicles give off more particulate matter (in form of black smoke) than gasoline-powered vehicles • Naturally: Volcanoes, forest fires, dust storms • Large Particulate matter is filtered by our nose and throats, but small particulate matter can be deposited deep within the respiratory tract • Can form Haze (reduced visibility) due to particulate matter scattering sunlight, and reduces light reaching Earth’s surface Photosythesis

  8. Particulate Matter cont. • Examples: ash from fires, asbestos from brakes and insulation, dust

Easily noticed: e.g. smokestacks

Can accumulate in lungs and interfere with the ability of lungs to exchange gases.

Some particulates are known carcinogens

Those working in dusty conditions at highest risk (e.g., miners)

Respirable Suspended Particulate Matter (RSPM) • -PM1 having size <= 1µm: effects in alveoli
-PM2.5 having size <= 2.5µm: effects trachea
-PM10 having size <= 10µm: effects in nasal part only • It is from the alveoli that the blood receives its oxygen http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-Delhi/Environmental%20Air%20Pollution/air%20pollution%20(Civil)/Module-1/3.htm

  9. The Year Without a Summer, 1816 • Volcanic Eruption in Indonesia (Java) • Result in major food shortage across the Northern Hemisphere

  10. Primary Pollutants • Polluting compounds that come directly out from the smoke stack, exhaust pipe, or natural emission source • Secondary Pollutants • Primary pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds

  11. Air Pollution comes from both natural and human sources. • Read p. 247-249 • Answer “Gauge Your Progress” Questions, p. 249

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